1. Field of the Invention
The present invention relates to a fluorescent-light image display method of and apparatus for measuring the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light and displaying an image representing the data relating to the target subject.
2. Description of the Related Art
Technologies have been proposed that make use of the fact that the intensity of the fluorescent-light emitted from a normal tissue differs from the intensity of the fluorescent-light emitted from a diseased tissue when a target subject is irradiated by a excitation light having a wavelength within the wavelength range of the internal color elements of the target subject, wherein, by receiving the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light having a wavelength within the wavelength range of the internal color elements of the target subject, the location and range of penetration of a diseased tissue is displayed as a fluorescent-light image.
Normally, when a target subject is irradiated by a excitation light, because a high-intensity fluorescent-light is emitted from a normal tissue, as shown by the solid line in FIG. 12, and a weak-intensity fluorescent-light is emitted from a diseased tissue, as shown by the broken line in FIG. 12, by measuring the intensity of the fluorescent-light emitted from aforementioned target subject, it can be determined whether the target subject is in a normal or a diseased state.
However, for cases in which the intensity of the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light is displayed as an image, because there is unevenness on the surface of a target subject, the intensity of the excitation light irradiating the target subject is not of a uniform intensity. Further, although the intensity of the fluorescent-light emitted from the target subject is substantially proportional to the intensity of the excitation light, the intensity of aforementioned excitation light becomes weaker in inverse proportion to the square of the distance between the excitation light and the target subject. Therefore, there are cases in which the fluorescent-light received from a diseased tissue located at a position closer to the excitation light source than a normal tissue is of a higher intensity than the fluorescent-light received from a fore mentioned normal tissue, and the state of the tissue of the target subject under examination cannot be accurately discerned based solely on the data relating to the intensity of the fluorescent-light received from the target subject upon the irradiation thereof with a excitation light. In order to remedy the problems described above, the applicants of the present application propose a method of dividing two types of fluorescent-light intensities obtained of different wavelength ranges to obtain the ratio therebetween, and displaying a computed-image based on the factor obtained thereby. That is to say: propose an image display method of displaying an image based on the difference in the form of the fluorescent-light spectra reflecting the tissue-state of a target subject; a method of displaying a fluorescent-light image comprising detecting the intensity of the reflected-light reflected from a target subject upon the irradiation thereof with a reference-light composed of light in the near-infrared spectrum, which shows uniform absorption characteristics for a wide variety of target subjects, obtaining the ratio between the intensity of the reference-light and the intensity of the fluorescent-light by division, and displaying a computed-image based on the factor obtained thereby, that is, an method of obtaining a value reflecting the yield of the fluorescent-light and displaying an image; and etc.
In addition, a fluorescent-light image display apparatus according to the technology described above basically comprises a light emitting means for projecting the excitation light and illuminating-light onto a target subject, a single image obtaining means provided with separate image obtaining portions for obtaining a fluorescent-light image formed of the fluorescent light emitted from the internal color elements of the target subject and a standard-image formed of the reflected-light reflected from the target subject upon the irradiation thereof by an illuminating-light, respectively, and a display means for displaying a fluorescent-light image and a standard-image obtained by the image obtaining means. In many cases, this apparatus is incorporated into an endoscope for insertion into a body cavity of a patient, a colposcope, or a surgical-use microscope, etc. According to an apparatus of such a configuration, generally, when a measurement is to be taken, first, while viewing a displayed standard-image, an operator inserts the insertion portion into a body cavity of a patient to the vicinity of the target subject of which a measurement is to be taken. Then, the excitation light is emitted and the intensity of the fluorescent-light emitted from the target subject is measured. After a measurement has been taken, while again viewing a display of a standard-image, the operator withdraws the insertion portion from the body of the patient.
Accordingly, from the insertion of the insertion portion until the removal thereof from the body of the patient, the standard-image displaying mode must be switched to in order to safely remove the insertion portion from the body of the patient.
However, in existing methods and apparatus for fluorescent-light image display, no safety measures against any kind of irregularity in the operation of the apparatus preventing an operator from obtaining a desired image have been proposed until now. Causes that can give rise to irregularities in the operation of the apparatus that can prevent the obtaining of a desired image include, irregularities in the imaging system, reductions in the output of the light source, malfunctions occurring in the mechanical components involved in the displaying of a standard-image, and irregularities in the controlling portion that controls the mechanical elements or the control signal line.
The present invention has been developed in consideration of the circumstances described above, and it is a primary object of the present invention to provide a method and apparatus for displaying a fluorescent-light image, wherein, even for cases in which an irregularity such as one of those described above causes a state to occur in which a desired image cannot be viewed, the insertion portion can be safely and expediently removed from the body of a patient and the safety of the patient and the operator can be ensured.
The fluorescent-light image display apparatus according to the present invention comprises: a excitation light emitting means for emitting excitation light; an illuminating-light emitting means for emitting illuminating-light; a light-guiding means for guiding the excitation light and the illuminating-light to the target subject of which a measurement is to be taken; an image obtaining means provided with separate image obtaining portions for obtaining a fluorescent-light image formed of the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light and a standard-image formed of the reflected-light reflected from the target subject upon the irradiation thereof by an illuminating-light, respectively; a display means for displaying a fluorescent-light image based on the obtained fluorescent-light image and a standard-image based on the obtained standard-image; and an image display controlling means for controlling the excitation light emitting means, the illuminating-light emitting means, the image obtaining means, and the display means; further comprising a excitation light irregularity detecting means for detecting an irregularity in the operation of the excitation light emitting means, a standard-image display controlling means for causing, in response to a detection signal from the excitation light irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched the standard-image obtaining mode, and the display means to be switched to the standard-image displaying mode.
Here, xe2x80x9cimage obtaining portionxe2x80x9d refers to a imaging element, and a mirror, etc. for guiding a fluorescent-light image or a standard-image to a imaging element; further, xe2x80x9cseparate image obtaining portionsxe2x80x9d refers to the separate imaging elements used for obtaining a fluorescent-light image and a standard-image, the separate mirrors used to guide a fluorescent-light image and a standard-image to their respective separate imaging elements, or the separate positions of a mirror, that is, the separate states for obtaining a fluorescent-light image and a standard-image. Further, there can be a plurality of each of fluorescent-light image obtaining portions and standard-image obtaining portions.
In addition, an irregularity in the operation of the excitation light to be detected by the excitation light irregularity detecting means can be an irregularity in the switching ON or OFF of the power source of the excitation light source, an irregularity occurring in the electric drive-current flowing to the light source thereof, an irregularity in the cooling apparatus (air-cooling fan or a Peltier element used in cooling, etc.) of the excitation light source (if an irregularity occurs in the cooling apparatus and the excitation light source is not cooled, the emission-output of the excitation light becomes weak and it becomes impossible to obtain a fluorescent-light image), or other operational irregularity relating to the drive apparatus of the excitation light source. In short, any irregularity causing the excitation light to be emitted only at an emission-output below a prescribed value or causing the excitation light to be in a non-emitted state, thereby preventing the obtaining of a fluorescent-light image qualifies.
Further, the causing of the illuminating-light to be emitted, the switching of the image obtaining means to the standard-image obtaining mode, and the switching of the display means to the standard-image displaying mode that are to be performed when an irregularity in the excitation light is detected, are performed when the illuminating-light emitting means, the image obtaining means, and the display means, respectively, are not in the aforementioned states.
Still further, according to the fluorescent-light image display apparatus described above, for cases in which a reference-light emitting means for emitting reference-light is provided, said apparatus can also be provided with an emission-output irregularity detecting means for detecting that an irregular operation has occurred in at least one of either the excitation light emitting means or the reference-light emitting means, and a standard-image display controlling means for causing, in response to an irregularity detection signal from the emission-output irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched to the standard-image obtaining mode, and the display means to be switched to the standard-image displaying mode. Further, in this case, the image obtaining means is provided with a separate image obtaining portion for obtaining fluorescent-light images, standard-images, and reflected-light images formed of the reflected-light reflected from a target subject upon the irradiation thereof by the reference-light, respectively.
Here, xe2x80x9cimage obtaining portionxe2x80x9d refers to a imaging element the same as that described above, and a mirror, etc. for guiding a fluorescent-light image, a standard-image, or a reflected-light image to a imaging element; further, xe2x80x9cseparate image obtaining portionsxe2x80x9d refers to the separate imaging elements used for obtaining a fluorescent-light image, a standard-image, and a reflected-light image, and the separate mirrors, etc. used to guide a fluorescent-light image and a standard-image to their respective separate imaging elements, or refers to the separate positions of a mirror, that is, the separate states for obtaining a fluorescent-light image, a standard-image, and a reflected-light image. Further, there can be a plurality of each of fluorescent-light image obtaining portions, standard-image obtaining portions, and reflected-light image obtaining portions.
Here, in addition to the irregularities described above occurring in the excitation light emitting means, the operational irregularities detected by the emission-output irregularity detecting means include irregularities relating to the operation of the reference-light source: irregularities in the switching ON or OFF of the power source of the reference-light source, an irregularity occurring in the electric drive-current flowing to the reference-light source, or other operational irregularity in the reference-light source drive apparatus, as well as weakening of the intensity or burning out of the reference-light source (a halogen lamp) with the passage of time. In short, any irregularity causing the reference-light to be emitted only at an emission-output below a prescribed value or causing the reference-light to be in a non-emitted state, thereby preventing the obtaining of a reflected-light image, qualifies.
Another fluorescent-light image display apparatus according to the present invention comprises: a excitation light emitting means for emitting excitation light; an illuminating-light emitting means for emitting illuminating-light; a light-guiding means for guiding the excitation light and the illuminating-light to the target subject of which a measurement is to be taken; an image obtaining means provided with separate image obtaining portions for obtaining a fluorescent-light image formed of the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light and a standard-image formed of the reflected-light reflected from the target subject upon the irradiation thereof by an illuminating-light, respectively; a display means for displaying a fluorescent-light image based on the obtained fluorescent-light image and a standard-image based on the obtained standard-image; and an image display controlling means for controlling the excitation light emitting means, the illuminating-light emitting means, the image obtaining means, and the display means; further comprising an image-obtainment irregularity detecting means for detecting an irregularity in the operation of either of the image obtaining portions, a standard-image display controlling means for causing, in response to a detection signal of the image-obtainment irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched to an image obtaining portion that is not operating irregularly, and the display means to be switched to the standard-image displaying mode.
Here, for cases in which there are a plurality of respective separate image obtaining portions for obtaining each of a fluorescent-light image and a standard-image, an image obtaining portion that is not operating irregularly is switched to, in an order of predetermined priority.
In addition, if the image-obtainment irregularity detecting means is a means for detecting operational irregularities in the image obtaining portions, it can be a means for detecting any type of operational irregularity occurring in an image obtaining portion: for example, for cases in which there is a mirror that moves to a different position for each respective imaging mode of imaging a fluorescent-light image or a standard-image, it can detect a mechanical malfunction such as an irregularity in the position of the mirror; or it can detect an electrical irregularity, such as either of the separate imaging elements being in a non-functional state; and etc.
Further, the causing of the illuminating-light to be emitted, the switching of the image obtaining means to the standard-image obtaining mode, and the switching of the display means to the standard-image displaying mode that are to be performed when an irregularity in one of the image obtaining portions is detected, are performed when the illuminating-light emitting means, the image obtaining means, and the display means, respectively, are not in the aforementioned states.
Still further, according to the fluorescent-light image display apparatus described above, for cases in which a reference-light emitting means for emitting a reference-light, and a reflected-light image obtaining portion for obtaining a reflected-light image of the reflected-light reflected from a target subject upon the irradiation thereof by a reference-light emitted from the reference-light emitting means have been provided, the apparatus can be further provided with an image-obtainment irregularity detecting means for detecting that an operational irregularity has occurred in one of the image obtaining means, and a standard-image display controlling means for causing, in response to a detection signal of the image-obtainment irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched the standard-image obtaining mode, and the display means to be switched to the standard-image displaying mode.
Yet another fluorescent-light image display apparatus according to the present invention comprises: a excitation light emitting means for emitting excitation light; an illuminating-light emitting means for emitting illuminating-light; a light-guiding means for guiding the excitation light and the illuminating-light to the target subject of which a measurement is to be taken; an image obtaining means provided with separate image obtaining portions for obtaining a fluorescent-light image formed of the fluorescent-light emitted from a target subject upon the irradiation thereof by a excitation light and a standard-image formed of the reflected-light reflected from the target subject upon the irradiation thereof by an illuminating-light, respectively; a display means for displaying a fluorescent-light image based on the obtained fluorescent-light image and a standard-image based on the obtained standard-image; and an image display controlling means for controlling the excitation light emitting means, the illuminating-light emitting means, the image obtaining means, and the display means; and a excitation light emission control line, an illuminating-light control line, an image-obtainment control line, and a display control line electrically connected to each of the excitation light emitting means, the illuminating-light emitting means, the image obtaining means, the display means, and the image display controlling means, wherein the illuminating-light emitting means emits the illuminating-light in response to the control signal of the illuminating-light control line being in the OFF state and the image obtaining means switches to the standard-image obtaining mode in response to the control signal of the image-obtainment control line being in the OFF state; further comprising a disconnection detecting means for detecting that at least one from among the illuminating-light control line, the image-obtainment control line and the display control line has become disconnected; and a standard-image controlling means for causing the control signal of the control lines from among the illuminating-light control line, the image-obtainment control line, and the display control line that have not been disconnected to be in the OFF state.
Here, xe2x80x9cdisconnectedxe2x80x9d refers to a physical break in a control line, a bad connection between the illuminating-light means, the image obtaining means, or the display means and the image display controlling means, and etc., that is, a state in which the image display controlling means cannot send a control signal to each of aforementioned means. Further, the xe2x80x9cOFF statexe2x80x9d refers to the state in which there is no control signal, due to aforementioned disconnection, or there is an electrical signal the same as the state in which there is no control signal.
Further, the standard-image display controlling means can be a means that causes the control signal of a control line that has not disconnected to be in the OFF state, or that causes the control signal of all the control lines to be in the OFF state.
Still further, as per the fluorescent-light image display apparatus described above, this is the same for cases in which a reference-light emitting means for emitting a reference-light is provided.
Further still, according to the fluorescent-light image display apparatus of the present invention, for cases in which an operational irregularity occurs in the image display controlling means, an input means is provided for causing the illuminating-light emitting means to emit the illuminating-light, the image obtaining means is switched to the standard-image obtaining mode and the display means to the standard-image displaying mode, wherein the standard-image display controlling means is a means for causing, in response to an input signal from the input means, the aforementioned illuminating-light emitting means to emit the aforementioned illuminating-light, and the image obtaining means to switch to the standard-image obtaining mode and the display means to switch to the standard-image displaying mode.
Here, the input means can be provided in combination with a reset switch for causing the image display controlling means to revert to the initial state.
In addition, although the display means of the fluorescent-light image display apparatus according to the present invention is provided with a single display apparatus for switching between displaying a fluorescent-light image and a standard-image, it can also be a means provided with two separate display apparatuses for displaying a fluorescent-light image and a standard-image, respectively.
Further, regarding the image-obtainment irregularity detecting means with which the fluorescent-light image display apparatus according to the present invention is provided, for cases in which the display means is provided with two separate display apparatuses for displaying a fluorescent-light image and a standard-image, respectively, the image-obtainment irregularity detecting means causes, in response to a detection signal indicating that an operational irregularity has occurred in one of the image obtaining portions, the display apparatus, from among the two display apparatuses, that has been displaying an image obtained by the image obtaining portion for which an operational irregularity has been detected to not display the image obtained by said image obtaining portion.
Still further, in response to a detection signal indicating that an operational irregularity has occurred in one of the image obtaining portions, the image display apparatus, from among the two display apparatuses, can be a display apparatus for displaying a freeze-frame image of the image obtained by the image obtaining portion for which an operational irregularity has been detected to have occurred.
Further still, the display apparatus, from among the two display apparatuses, that has been displaying an image obtained by the image obtaining portion for which an operational irregularity has been detected can be a display apparatus for displaying, in response to a detection signal indicating that an operational irregularity has occurred in one of the image obtaining portions, a message indicating that an operational irregularity has occurred in said image obtaining portion.
Additionally, according to the fluorescent-light image display apparatus of the present invention, the excitation light is a GaN semiconductor laser beam.
According to a fluorescent-light image display apparatus of a configuration described above according to the present invention, a excitation light irregularity detecting means is provided for detecting an operational irregularity occurring in the excitation light emitting means, and in response to a detection signal therefrom indicating that an operational irregularity has occurred in the excitation light emitting means, the illuminating-light is caused to be emitted from the illuminating-light emitting means, the image obtaining means is caused to be switched the standard-image obtaining mode, and the display means is caused to be switched to the standard-image displaying mode, whereby a standard-image is displayed; therefore, the standard-image displaying mode can be automatically switched to when an operational irregularity in the excitation light emitting means is detected: For example, for cases in which the fluorescent-light image display apparatus according to the present invention is implemented in a fluorescent endoscope apparatus, the endoscope insertion portion thereof can be safely removed from the body of a patient while an operator views a standard-image.
In addition, for cases in which a reference-light emitting means for emitting reference-light is provided, an emission-output irregularity detecting means for detecting that an operational irregularity has occurred in at least one of the excitation light emitting means or the reference-light emitting means is provided, and by causing, in response to a detection signal from the emission-output irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched the standard-image obtaining mode, and the display means to be switched to the standard-image displaying mode, a standard-image is displayed, whereby the same effect as described above can be obtained.
Further, according to the fluorescent-light image display apparatus of the present invention, an image-obtainment irregularity detecting means for detecting that an operational irregularity has occurred in one of the image obtaining portions is provided, and by causing, in response to a detection signal from the image-obtainment irregularity detecting means, the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to be switched the standard-image obtaining mode, and the display means to be switched to the standard-image displaying mode, whereby a standard-image is displayed, an operational irregularity occurring in an image obtaining portion can be detected, and because the image obtaining means is automatically switched, in corresponding to said operational irregularity, to an image obtaining portion that is not operating irregularly, even for cases in which an operational irregularity occurs in the image obtaining portion involved in the displaying of a standard-image, by using an image obtaining portion that is not malfunctioning, it is possible to continuously display a standard-image.
Still further, according to the fluorescent-light image display apparatus described above, for cases in which a plurality of image obtaining portions are provided, even when an image obtaining portion malfunctions, because one of the plurality of image obtaining portions that is not malfunctioning can be switched to, continuous displaying of a standard-image can be performed with even higher reliability. For example, for a case in which three image obtaining portions are provided, a standard-image can be displayed while as many as 2 of said 3 image obtaining portions are malfunctioning.
Further still, according to the fluorescent-light image display apparatus of the present invention: the illuminating-light emitting means is a means that emits, in response to the control signal of the illuminating-light emission control line being in the OFF state, the illuminating-light; the image obtaining means is a means that switches, in response to the control signal of the image-obtaining control line being in the OFF state, to the standard-image obtaining mode; the display means is a means that switches, in response to the control signal of the display control line being in the OFF state, to the standard-image displaying mode; further comprising a disconnection detecting means for detecting that at least one control line from among the illuminating-light emission control line, the image-obtainment control line, and the display control line has been disconnected; wherein, because in response to a detection signal from the disconnection detecting means, the control signal of the control lines from among the illuminating-light emission control line, the image-obtainment control line, and the display control line that have not been disconnected are caused to be in the OFF state, and the standard-image displaying mode can be switched to, a disconnection in any of the control lines of the apparatus can be detected, and even for cases in which a control line that relays a control signal involved in the displaying of a standard-image is disconnected, a standard-image can be continuously displayed.
Additionally, when a malfunction occurs in the image display controlling means, an input means is provided for causing the illuminating-light to be emitted from the illuminating-light emitting means, the image obtaining means to switch to the standard-image obtaining mode and the display to switch to the standard-image displaying mode, wherein, because in response to an input signal from the input means, the illuminating-light emitting means is caused to emit illuminating-light, the image obtaining means is switched to the standard-image obtaining mode and the display means is switched to the standard-image displaying mode, and a standard-image can be displayed, even for cases in which the image display controlling means that outputs a control signal involved in the displaying of a standard-image malfunctions, by an input operation performed by an operator, a standard-image can be manually caused to be displayed.
Further, according to the fluorescent-light image display apparatus of the present invention, because the display means can be a single display apparatus that switches between displaying a fluorescent-light image and a standard-image, the cost of the apparatus can be reduced.
Still further, because the display means of the fluorescent-light image according to the present invention can be two separate display apparatus that displays a fluorescent-light image and a standard-image, respectively, two images can be viewed at the same time, and comparative analysis is possible.
Further still, with regard to the image-obtainment irregularity detecting means with which the fluorescent-light image display apparatus described above is provided, for cases in which the display means is provided with a 2-screen display apparatus for displaying a fluorescent-light image and a standard-image, respectively, in response to a malfunction detection signal indicating that one of the image obtaining portions has malfunctioned, because the screen, from among the two display screens, that had been displaying an image obtained by the image obtaining portion detected to have malfunctioned can be caused to not display an image or to display a freeze-frame image, a mistake in judgment on the part of an operator or confusion caused by the displaying of images due to a malfunction in an image obtaining portion can be avoided. Further, because it is possible to display a message indicating that an operational irregularity has occurred in an image obtaining portion, the operator is able to recognize that an operational irregularity has occurred in said image obtaining portion.
Even further, by using excitation light having a wavelength in the 380-420 wavelength range, which is outside of the light intensity characteristic of a normal-tissue, more reliable data of a normal-tissue can be obtained. Further, by using a GaN semiconductor laser, the size of the apparatus can be made compact and the cost reduced.